1. Field of the Invention
This invention relates to apparatus and a method for introducing implants such as radioactive seeds, or pellets or dissolvable capsules carrying medication or transgenes, into soft tissue such as tumors, and particularly intra-abdominal or intrathoracic tumors. Specifically, it relates to such an apparatus and method which deposits multiple implants in soft tissue with precise, selectable spacing between implants.
2. Background Information
It is known to inject radioactive seeds into the prostate to treat malignancies. Early devices for this purpose injected a single seed using a hollow needle from which the seed was ejected by a plunger. Later devices have the capability of introducing multiple seeds. Some deposit a single elongated implant having multiple seeds distributed longitudinally. Others have a plunger with multiple, axially spaced seed cavities inserted through a cannula with equally spaced side openings for laterally discharging the seeds. Neither of these approaches offer flexibility in the spacing between multiple implants. Furthermore, there is difficulty in laterally discharging the implants in the second arrangement. It has been proposed to incorporate small leaf springs in the cavities to push the implants clear of the cannula, but withdrawing the cannula past the seeds disturbs their positions and the diameter of the cannula must be enlarged to accommodate the springs. Still other multiple seed ejectors rely upon the user to set the spacing between seeds. The accuracy of this technique is dependent upon the skill of the user or requires fluoroscopy to monitor seed location.
There is a need for an improved apparatus for introducing implants into soft tissue.
There is a particular need for an improved apparatus for introducing multiple implants at precisely spaced locations within the soft tissue.
There is a related need for such apparatus with which the spacing between implants can be easily and accurately adjusted.
There is also a need for such apparatus which can be used to introduce implants into soft tissue within a cavity such as intra-abdominal and intrathoracic tumors.
There is an additional need for such apparatus which can be easily loaded and simple to use, and particularly which only requires one hand of the user to deposit the implants with precise spacing.
There is a further need for such a device which can be used for various types of implants, such as radioactive seeds, or pellets bearing or dissolvable capsules containing medications or transgenes.